GIS Team

Calculating Michigan Shoreline

*Numbers were corrected on January 26, 2016 to fix a small found error in the processing. The shoreline distance for 10 counties changed slightly, mostly in the 'inland lakes' number between a fraction of a mile up to about 5.42 miles.

To calculate Great Lakes shoreline meters per county: The county shapefile was converted from polygons to lines. Then we selected those lines that intersected with the Great Lakes shapefile. Save as a new shapefile, keeping the county name attributes. Add field to the resulting attribute table and calculate geometry.

To calculate inland lake shoreline meters per county: Perform a union with the county layer, then convert to lines and select those lines that share a line segment with a county boundary and delete them. Save as a new shapefile, keeping the county name attributes. Add a field to the resulting attribute table and calculate geometry.

These numbers vary from NOAA's statewide estimate of 3,224 miles, we believe because we included the shores of all Michigan islands present in the shapefiles and because of the differing methodology.